document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=421429>Question 421429</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a multiple-choice test, each question has five options. Students will get 10 points for each correct answer; lose 2 point for each incorrect answer; and receive no points for unanswered questions. A student does not know the correct answer for one question. Is it to her advantage or disadvantage to guess an answer? Show your calculations for expected value. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #294294 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=294294\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In a multiple-choice test, each question has five options. <BR>\n" );
document.write( "Students will get 10 points for each correct answer; lose 2 point for each incorrect answer; and receive no points for unanswered questions. <BR>\n" );
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document.write( "A student does not know the correct answer for one question. Is it to her advantage or disadvantage to guess an answer? Show your calculations for expected value.<BR>\n" );
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document.write( "Random Values: 10 ; -2, ; 0<BR>\n" );
document.write( "Probabilities: 1/4; 4/5 ; 0<BR>\n" );
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document.write( "E(x) = (1/5)10 - (4/5)2<BR>\n" );
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document.write( "E(x) = 2 - 8/5<BR>\n" );
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document.write( "E(x) = 10/5 - 8/5 = 2/5 = 0.4<BR>\n" );
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document.write( "She should guess<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "============ </SPAN>\n" );
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